How the EV charging cost calculator works
The cost to charge depends on how much energy you add and what your utility charges per kilowatt-hour. Enter your battery size, the charge window you want (say 20% to 80%), and your electricity price, and the calculator multiplies the energy drawn from the grid by your rate. It also adds a charging-efficiency factor, because a few percent is always lost as heat between the wall and the battery.
The numbers you need
- Battery capacity — your pack size in kWh, from the spec sheet (e.g. 75 kWh).
- Charge window — daily charging is usually 20% to 80% to protect the battery, not 0% to 100%.
- Electricity price — your per-kWh rate; check for cheaper overnight or off-peak windows.
- Charging efficiency — AC home charging runs around 85 to 90%, so grid energy is a bit higher than what lands in the battery.
Home charging vs public fast charging
Charging at home on a Level 2 unit is almost always the cheapest option, often a third of the cost of a public DC fast charger. Fast chargers price in convenience and demand fees, so use this calculator with the public rate to see the gap before a road trip.
Cost per mile
Enter your efficiency in miles per kWh and the calculator also shows cost per mile and per 100 miles — the cleanest way to compare against a gas car. To compare with gasoline directly, try the Cost Per Mile Calculator, and to estimate how long a session takes, use the EV Charging Time Calculator.
Frequently asked questions
Why is grid energy higher than energy added?
Charging is not perfectly efficient. At 90% efficiency, putting 45 kWh into the battery pulls about 50 kWh from the grid, and you pay for the full 50.
Should I charge to 100%?
For daily use most makers suggest 80% to extend battery life, saving 100% for trips. This calculator lets you set any window so you can price either.
Does cold weather change the cost?
Yes. Cold reduces efficiency and adds battery heating load, so winter charging costs more per mile than the same trip in mild weather.